Citex was rumoured by City sources to have pulled out of the bidding after Atkins' £12m offer. Sources close to Mace insisted that "nobody was out of the picture", but conceded that Atkins was favourite to buy the company.
One source said: "Atkins will get Mace. It is not cut and dried, but it is without doubt the one to put your money on."
Mace refused to comment on the talks. Citex and WS Atkins also declined to comment.
Mace is known to be keen to develop into a multipurpose service provider, and industry sources say Atkins is tailor-made for that role.
One source said: "At £12m, it is not paying for Mace what it would have paid for Bovis. It will have a fair bit in the bank, which will give Mace the financial clout it lacks now." City sources added that they expected Atkins to announce a US purchase within a week.
The news comes at the same time as Mace deputy chairman Ian Wylie, one of the company's founders, announced his retirement. Wylie said he would leave once Mace had finished the £100m Merrill Lynch headquarters in London's Square Mile in 2001.
Wylie, who owns a number of shares, denied that his departure was linked to any potential buyout. He said: "We always had stated aims as to when we wanted to retire. Ian's [Macpherson] was to retire at 55. My own was to stop at 60."
When asked if he would seek to sell his stake, Wylie said: "What I do with my shares depends on circumstances nearer the time.”